1. Field of the Invention
The present invention relates to a process control technique for use in production management of semiconductor devices, liquid crystal substrates and the like, and more particularly, to a process control device and a process control method permitting changes in processing orders, processing conditions and the like during a manufacturing process.
2. Description of the Background Art
In recent years, most semiconductor devices and liquid crystal substrates have been manufactured automatically. Thus, the function of a process control device controlling such process largely affects the production efficiency. Generally, production management in a production line is done by causing a process control device to memorize reference information such as processing orders and processing conditions of products for each kind of product, and to control those processing orders and conditions according to the reference information.
In a conventional process control device, such reference information must be changed when a processing order or processing condition of a product is added or altered. When changing the reference information without halting the manufacturing process, however, unfinished items are still in the respective process steps defined by the presently active reference information. Therefore, the entire manufacturing process must be halted before changing the reference information. In addition, an operator must decide whether the change in the reference information can be applied to the items in the process, and if so, the operator needs to perform the operation required for that change manually.
As described above, the change of the reference information in a conventional process control device leads to deterioration in the efficiency of the operation, and in the worst case, such altered reference information may not have been applied to some of the finished products. Techniques addressing such a problem include those disclosed in Japanese Patents Laying-Open Nos. 6-290085 and 9-320918.
The invention disclosed in the Japanese Patent Laying-Open No. 6-290085 relates to a lot management method in which working data stored in a database are read out to designate working condition for each work on respective manufacturing lots. A validation date and an invalidating date for the working data are stored in a file layout of the working data, and the work is performed only between those dates.
The invention disclosed in the Japanese Patent Laying-Open No. 9-320918 relates to a production control system that allows automatic, collective change of manufacturing conditions when changing the conditions on manufacturing steps of a plurality of kinds of articles, by a combined pattern of kind of article, process and manufacturing condition.
The invention disclosed in the Japanese Patent Laying-Open No. 6-290085, however, is unable to address an accidental case in which there arises an improper or defective processing condition, for example, since it is required to set in advance the validating and invalidating dates. In addition, the invention does not solve the problem that, at the time when the data becomes invalid, items in process remain unfinished, as described above.
The invention disclosed in the Japanese Patent Laying-Open No. 9-320918 allows collective change of common part data for respective process procedures by the combined pattern of the kind of article, process and manufacturing condition. However, it also is unable to deal with the case of an improper processing condition, and again, it does not solve the problem with the unfinished items in process.
An object of the present invention is to provide a process control device permitting processing orders and processing conditions to be changed even when individual items are in respective manufacturing steps.
Another object of the present invention is to provide a process control method permitting processing orders and processing conditions to be changed even when individual items are in respective manufacturing steps.
According to an aspect of the present invention, the process control device includes: a change table detection unit that determines whether there exists, corresponding to a progress file representing a manufacturing state, a change table containing the content of change for the progress file; a progress file adjustment unit that changes, when the change table detection unit determines that there exists a change table, the content of the progress file according to the content in the change table; a unit that controls a transport device of items in process based on the progress file changed by the progress file adjustment unit; and a unit that controls a manufacturing device of the items based on the progress file changed by the progress file adjustment unit.
The above manufacturing device control unit controls the manufacturing device based on the progress file that has been changed by the progress file adjustment unit. Accordingly, it is possible to change processing orders, processing conditions and others even when items are in respective manufacturing steps.
According to another aspect of the present invention, the process control method includes the steps of: determining whether there exists, corresponding to a progress file representing a manufacturing state, a change table containing the content of change for the progress file; changing, when determined that there exists a change table, the content of the progress file according to the change table; controlling a transport device of items based on the changed progress file; and controlling a manufacturing device of items based on the changed progress file.
Since the manufacturing device is controlled according to the progress file that has been changed, it is possible to change processing orders, processing conditions and the like even when items are in respective manufacturing steps.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.